Engine cooling fan

ABSTRACT

The drawings illustrate an engine cooling fan which decreases in overall diameter in response to increased engine speed as a result of a centrifugal weight-actuated camming arrangement.

6/1935 Mayo 415/12 Unlted States Patent 1191 1111 3,763,835 Miller et al. Oct. 9, R973 ENGINE COOLING FAN 2,178,405 10/1939 Reggie 415/130 1751 W Mmer Livmdm 3'33??? 3/1321 $2,522?fi iijiiiiiiii tj' HQ/33 Goya, Pmmac, both of Mlch- 3,358,773 12/1967 O1dberg.... 416/88 3,561,883 2/1971 B 416 87 X [73] Assignee: General Motors Corporation, I

7 Detroit, Mich. FOREIGN PATENTS OR APPLICATIONS [22] F Aug 2 H72 812,911 5/1959 Great Britain. 415/36 [21] APPL N05 277,415 Primary Examiner-AI Lawrence Smith Attorney-Warren E. Finken et a1. [52] US. Cl 123/4141, 415/133, 416/87 [51] Ill. Cl. F0lp 7/02, F0411] 29/36 57 ABSTRACT [58] Field ofSelrch l23/4I.ll,4l.12,

123/4149 41 5; 4 7 88, 9; 415 129 The drawmgs lllustrate an engme coolmg fan wh1ch 130 133 12 3 decreases in overall diameter in response to increased engine speed as a result of a centrifugal weight- 5 References Cited actuated cammin'g arrangement.

UNITED STATES PATENTS 8 u 7 Drawing Figures 2,005,193

ENGINE'COOLING FAN The invention relates generally to engine cooling fans and, more particularly, to variable diameter fans.

While engine cooling is generally accomplished by either a viscous fluid clutch-driven or a flexible blade fan, it is desirable to combine the good qualities of each in a variable diameter fan arrangement, i.e., substantially reducing high speed fan tip noise while increasing the cooling characteristics at low engine speed when ambient temperature is generally high.

Accordingly, an object of the invention is to provide an improved engine cooling fan having variable length blades which automatically decrease in diameter in response to increased engine speed.

Another object of the invention is to provide an improved variable diameter fan including a centrifugal force-actuated camming arrangement for automatically' varying the overall diameter thereof.

A further object of the invention is to provide a variable diameter fan including four spaced discs, two being interconnected and having radial grooves formed therein, and the other two being interconnected and having spiral grooves formed therein, with a pair of spring-loaded centrifugal weights mounted on a pair of pins extending through adjacent radial and spiral grooves of two of the four discs, while a plurality of blades are radially slidably mounted on a plurality of pins extending through adjacent radial and spiral grooves of the other two of the four discs, the spiral grooves being arranged such that outward movement of the weights effects inward movement of the blades.

These and other objects and advantages of the inven tion will be apparent when reference is made to the following description and accompanying drawings, wherein:

FIG. 1 is a front view of an engine cooling fan embodying the invention;

FIG.'2 is a cross-sectional view taken along the plane of line 22 of FIG. 1, and looking in the direction of the arrows;

FIG. 3 is a view taken along the plane of line 3-3 of FIG. I, and looking in the direction of the arrows; and

FIGS. 4-7 are views illustrating various operational positions for the cooperating moving parts of the fan.

Referring to the drawingsin greater detail, FIGS. 1 and 2 illustrate an engine cooling fan I having an engine-driven shaft 12 on which four discs 14, 16, 18, and 20 are mounted. The discs 14 and 20 are secured directly to the shaft 12 at predetermined spaced positions thereon, while the discs 16 and 18 are located intermediate the discs 14 and 20 and each secured to a sleeve 22 which is rotatably mounted on the shaft 12.

As illustrated in FIGS. 4-7, a .pair of oppositely disposed radial slots or grooves 24 are formed in disc 14, while a plurality, for example, seven, unequally spaced radial slots or grooves 26 are formed in the disc 20. Two oppositely disposed arcuate or spiral slots or grooves 28 are formed in the disc 16 for cooperation with the radial slots 24, while a plurality of arcuate or spiral slots or grooves 30 are formed in the disc 18 generally axially aligned with a plurality of radial slots 26 of the disc 20. The slots 30 are spiralled in the opposite direction from that of the slots 28.

A pair of pins 32 are mounted so as to extend through respective adjacent aligned radial slots 24 and spiral slots 28' of the respective adjacent discs 14 and 16. A set of pins 34 are mounted so as to extend through re spective adjacent aligned radial slots 26 and spiral slots 30 of the adjacent discs 18 and 20. Another set of pins 36 is secured or formed on the disc 20, extending axially therefrom away from the disc 18.

A plurality ofblades 38, each having a radially extending support stem or linkage member 40, are mounted for rotation with the disc 20, the inner end 42 of each stem 40 being secured to a respective pin 34. A radial slot 44 is formed in, each stem 40 and/or each blade 38, with the fixed pins 36 extending respectively therethrough to serve as a guide means for the slidable blades 38.

A pair of centrifugal weight members 46 are mounted on the respective pins 32 adjacent the disc 14 on the side thereof opposite the 'disc 16. Suitable resilient means, such as a coil spring 48, is mounted around a concave-shape radially outer surface 50 formed on each of the weight members 46 urging the weight members 46 toward their most radial inward position.

It may be noted in FIG. 3 that each of the blades 38 is shaped in the form of an airfoil in the conventional manner. The stem 40 and hence the pins 34 and 36 may be located at the midpoint of the arcuate width of the respective blades 38, as illustrated, or, if desired, could be located closer to the leading edge 52 of each blade 38, depending upon the desired curvature of each blade 38.

OPERATION So long as the engine is running at a predetermined low speed, the spring 48 will hold the centrifugal weight members 46 at their most radially inward position, as limited by the pins 32 in the respective most radial inward portion of the two radial grooves 24 of the disc 14 and the two spiral grooves 28 of the disc 16. Under this condition, the other set of pins 34 are mounted through the adjacent discs 18 and 20 so as to be mounted at the most radial outward portion of the respective adjacent radial grooves 26 and spiral grooves 30. Since the pins 34 are secured to the inner end 42 of the respective blade stems 40, under this condition the blades 38 will be positioned at their most radial outward position, thus producing the maximum engine cooling effect.

As the speed of the engine increases, at a predetermined higher speed, the eight members 46 will be urged outwardly under the action of centrifugal force, against the force of the spring 48. As the weight members 46 and their respective connected pins 32 move outwardly, it may be realized from FIGS. 4 and 5 that the disc 16 will be caused to rotate with respect to the disc 14 by virtue of the pins 32 forcing the radial slots 24 and the cooperating spiral slots 28 to remain progressively aligned at th e axis of the pins 32. Since the disc 18 is mounted for rotation with the disc 16 through the spacer 22, and since the spiral slots 30 are arced in the opposite direction to that of the spiral slots 28, the pins 34 will be progressively forced inwardly along the respective spiral slots 30 and the cooperating radial slots 26, thereby pulling the respective stems 40 and blades 38 radially inwardly, reducing the overall diameter of the fan 10 to effectuate a substantially reduced fan noise condition.

Once the engine speed reduces, the spring 48 pulls the weight members 46 radially inwardly resulting in the blades 38 returning outwardly.

It should be apparent that the invention provides a novel camming arrangement for causing the blades of an engine cooling fan to retract to a smaller overall diameter in response to increased centrifugal force and to increase in overall diameter upon a reduction in engine speed.

While but one embodiment of the invention has been shown and described, it. should be apparent that other arrangements would be possible within the scope of the invention, such as the interchange and/or realignment of the discs, and different interconnecting means for the respective radially slotted and spirally slotted discs. Furthermore, the disc could consist of a hub having fixed radial blade portions formed thereon adaptable for the slidable mounting thereon of the respective curved blades 38.

We claim:

1. An engine cooling fan comprising a shaft, a first pair of discs at least one of which is secured to said.

shaft, a second pair of discs rotatably mounted on said shaft, a plurality of fan blades slidably mounted on one of said four discs, centrifugal weight means slidably mounted on another of said four discs, and camming means formed on said four discs and operatively connected to said plurality of fan blades and to said centrifugal weight means for causing said plurality of fan blades to move in the opposite radial direction to that of said centrifugal weight means under the action of centrifugal force.

2. An engine cooling fan comprising a shaft, a first pair of discs secured to said shaft, a second pair of discs rotatably mounted on said shaft, a plurality of fan blades slidably mounted on one of said four discs, centrifugal weight means slidably mounted on another of said four discs, camming means fonned on said four discs, and pin means operatively mounted in said camming means and connected to said fan blades and to said centrifugal weight means for causing said plurality of fan blades to move in the opposite radial direction to that of said centrifugal weight means under the action of centrifugal force.

3. An engine cooling fan comprising a shaft, a first pair of discs secured to said shaft, a second pair of discs rotatably mounted on said shaft, a plurality of fan blades slidably mounted on one of said four discs, centrifugal weight means slidably mounted on another of said four discs, radial camming means formed on one of said pairs of discs, spiral camming means formed on the other of said pairs of discs, first pin mean operatively connected to one of each of said pairs of discs and to said centrifugal weight means, and second pin means operatively connected to the other of each of said pairs of discs and to said fan blades, said first and second pin means serving to move said plurality of fan blades in the opposite radial direction to that of said centrifugal weight means underthe action of centrifugal force.

4. An engine cooling fan comprising a shaft, a first pair of discs secured to said shaft, a second pair of discs interconnected and rotatably mounted on said shaft, a plurality of fan blades slidably mounted on one of said four discs, a pair of weight members slidably mounted on another of said four discs, a plurality of radial slots formed on each of one of said pairs of discs, a plurality of spiral slots formed on each of the other of said pairs of discs, a pair of pins mounted in adjacent radial and spiral slots of one of each of said pairs of discs and secured to said respective weight members, and a plurality of pins mounted in adjacent radial and spiral slots of the other of each of said pairs of discs and secured to said respective fan blades, said pair of pins and said plurality of pins serving to move said plurality of fan blades in the opposite radial direction to that of said weight members under the action of centrifugal force.

5. The engine cooling fan describedin claim 4, and a spring interconnecting said pair of weight members to return said weight members radially inwardly upon a decrease in centrifugal force.

6. An engine cooling fan comprising an engine-driven shaft, a first pair of discs secured to said shaft, a second pair of discs rotatably mounted on said shaft, connector means between said second pairs of discs, a plurality of fan blades slidably mounted on one of said first pair of discs, a pair of weight members slidably mounted on the other of said first pair of discs, a pair of radial camming slots formed on said other of said first pair of discs, a pair of spiral camming slots formed on one of said second pair of discs, a plurality of unequally spaced radial camming slots formed on said one of said first pair of discs, a plurality of unequally spaced spiral camming slots formed on the other of said second pair of discs, said pair and said plurality of spiral camming slots being formed in opposite directions, a pair of op positely disposed pins mounted in adjacent radial and spiral camming slots and secured to said respective weight members, a plurality of pins mounted in adjacent pluralities of radial and spiral camming slots and secured to said fan blades, said pair of pins and said plurality of pins serving to move said plurality of fan blades in the opposite radial direction to that of said weight members under the action of centrifugal force, and a return spring interconnecting said pair of weight members.

7. An engine cooling fan comprising an enging speedproportional shaft, a first disc secured adjacent the free end of said shaft, a pair of oppositely disposed radial grooves formed in said first disc, a second disc rotatably mounted on said shaft adjacent said first disc, a pair of oppositely disposed spiral grooves formed in said second disc, a third disc rotatably mounted on said shaft adjacent said second disc, a plurality of unequally spaced spiral grooves formed in said third disc, said plurality of spiral grooves being arced in the opposite direction to that of said pair of spiral grooves, a connector member between said second and third discs, a fourth disc secured to said shaft adjacent said third disc, a plurality of unequally spaced radial grooves fromed in said fourth disc, a pair of pins slidably mounted in said respective adjacent pair of radial and spiral grooves, a pair of centrifugal weight mounted on said respective pair of pins adjacent said first disc, a

spring interconnectingsaid pair of centrifugal weights, a plurality of pins slidably mounted in said respective.

adjacent plurality of radial and spiral grooves, a plurality of linkage members secured to said respective plurality of pins adjacent said fourth disc, and a plurality of fan blades secured to the outer ends of said respective plurality of linkage members.

8. An engine cooling fan comprising an engine-driven shaft, a first disc secured adjacent the free end of said shaft, a pair of oppositely disposed radial camming slots formed in said first disc, a sleeve member rotatably mountedon said shaft having one end thereof adjacent said first disc, a second disc secured to said sleeve member, a pair of oppositely disposed spiral camming slots formed in said second disc, a third disc secured to said sleeve member adjacent said second disc, a plurality of unequally spaced spiral camming slots formed in said third disc, said plurality of spiral camming slots being arced in the opposite direction to that of said pair of spiral camming slots formed in said second disc, a fourth disc secured to said shaft adjacent the other end of said sleeve member, a plurality of unequally spaced radial camming slots formed in said fourth disc, a pair of pins slidably mounted in said respective adjacent pair of radial and spiral camming slots, a pair of centrifugal weight members mounted on said respective pair of pins adjacent said first disc, a return spring interconnecting said pair of centrifugal weight members, a first plurality of pins slidably mounted in said respective adjacent plurality of radial and spiral camming slots, a second plurality of pins secured to said fourth disc, a plurality of linkage members secured to said respective first plurality of pins adjacent said fourth disc and slidably mounted on said second plurality of pins, and a plurality of fan blades secured to the outer ends of said respective plurality of linkage members, the resultant camming action of said cooperating radial and spiral camming slots causing said plurality of fan blades to move radially inwardly to decrease the overall diameter thereof in response to the radial outward movement of said centrifugal weight members under the action of centrifugal force. 

1. An engine cooling fan comprising a shaft, a first pair of discs at least one of which is secured to said shaft, a second pair of discs rotatably mounted on said shaft, a plurality of fan blades slidably mounted on one of said four discs, centrifugal weight means slidably mounted on another of said four discs, and camming means formed on said four discs and operatively connected to said plurality of fan blades and to said centrifugal weight means for causing said plurality of fan blades to move in the opposite radial direction to that of said centrifugal weight means under the action of centrifugal force.
 2. An engine cooling fan comprising a shaft, a first pair of discs secured to said shaft, a second pair of discs rotatably mounted on said shaft, a plurality of fan blades slidably mounted on one of said four discs, centrifugal weight means slidably mounted on another of said four discs, camming means formed on said four discs, and pin means operatively mounted in said camming means and connected to said fan blades and to said centrifugal weight means for causing said plurality of fan blades to move in the opposite radial direction to that of said centrifugal weight means under the action of centrifugal force.
 3. An engine cooling fan comprising a shaft, a first pair of discs secured to said shaft, a second pair of discs rotatably mounted on said shaft, a plurality of fan blades slidably mounted on one of said four discs, centrifugal weight means slidably mounted on another of said four discs, radial camming means formed on one of said pairs of discs, spiral camming means formed on the other of said pairs of discs, first pin means operatively connected to one of each of said pairs of discs and to said centrifugal weight means, and second pin means operatively connected to the other of each of said pairs of discs and to said fan blades, said first and second pin means serving to move said plurality of fan blades in the opposite radial direction to that of said centrifugal weight means under the action of centrifugal force.
 4. An engine cooling fan comprising a shaft, a first pair of discs secured to said shaft, a second pair of discs interconnected and rotatably mounted on said shaft, a plurality of fan blades slidably mounted on one of said four discs, a pair of weight members slidably mounted on another of said four discs, a plurality of radial slots formed on each of one of said pairs of discs, a plurality of spiral slots formed on each of the other of said pairs of discs, a pair of pins mounted in adjacent radial and spiral slots of one of each of said pairs of discs and secured to said respective weight members, and a plurality of pins mounted in adjacent radial and spiral slots of the other of each of said pairs of discs and secured to said respective fan blades, said pair of pins and said plurality of pins serving to move said plurality of fan blades in the opposite radial direction to that of said weight members under the action of centrifugal force.
 5. The engine cooling fan described in claim 4, and a spring interconnecting said pair of weight members to return said weight members radially inwardly upon a decrease in centrifugal force.
 6. An engine cooling fan comprising an engine-driven shaft, a first pair of discs secured to said shaft, a second pair of discs rotatably mounted on said shaft, connector means between said second pair of discs, a plurality of fan blades slidably mounted on one of said first pair of discs, a pair of weight members slidably mounted on the other of said first pair of discs, a pair of radial camming slots formed on said other Of said first pair of discs, a pair of spiral camming slots formed on one of said second pair of discs, a plurality of unequally spaced radial camming slots formed on said one of said first pair of discs, a plurality of unequally spaced spiral camming slots formed on the other of said second pair of discs, said pair and said plurality of spiral camming slots being formed in opposite directions, a pair of oppositely disposed pins mounted in adjacent radial and spiral camming slots and secured to said respective weight members, a plurality of pins mounted in adjacent pluralities of radial and spiral camming slots and secured to said fan blades, said pair of pins and said plurality of pins serving to move said plurality of fan blades in the opposite radial direction to that of said weight members under the action of centrifugal force, and a return spring interconnecting said pair of weight members.
 7. An engine cooling fan comprising an engine speed-proportional shaft, a first disc secured adjacent the free end of said shaft, a pair of oppositely disposed radial grooves formed in said first disc, a second disc rotatably mounted on said shaft adjacent said first disc, a pair of oppositely disposed spiral grooves formed in said second disc, a third disc rotatably mounted on said shaft adjacent said second disc, a plurality of unequally spaced spiral grooves formed in said third disc, said plurality of spiral grooves being arced in the opposite direction to that of said pair of spiral grooves, a connector member between said second and third discs, a fourth disc secured to said shaft adjacent said third disc, a plurality of unequally spaced radial grooves formed in said fourth disc, a pair of pins slidably mounted in said respective adjacent pair of radial and spiral grooves, a pair of centrifugal weights mounted on said respective pair of pins adjacent said first disc, a spring interconnecting said pair of centrifugal weights, a plurality of pins slidably mounted in said respective adjacent plurality of radial and spiral grooves, a plurality of linkage members secured to said respective plurality of pins adjacent said fourth disc, and a plurality of fan blades secured to the outer ends of said respective plurality of linkage members.
 8. An engine cooling fan comprising an engine-driven shaft, a first disc secured adjacent the free end of said shaft, a pair of oppositely disposed radial camming slots formed in said first disc, a sleeve member rotatably mounted on said shaft having one end thereof adjacent said first disc, a second disc secured to said sleeve member, a pair of oppositely disposed spiral camming slots formed in said second disc, a third disc secured to said sleeve member adjacent said second disc, a plurality of unequally spaced spiral camming slots formed in said third disc, said plurality of spiral camming slots being arced in the opposite direction to that of said pair of spiral camming slots formed in said second disc, a fourth disc secured to said shaft adjacent the other end of said sleeve member, a plurality of unequally spaced radial camming slots formed in said fourth disc, a pair of pins slidably mounted in said respective adjacent pair of radial and spiral camming slots, a pair of centrifugal weight members mounted on said respective pair of pins adjacent said first disc, a return spring interconnecting said pair of centrifugal weight members, a first plurality of pins slidably mounted in said respective adjacent plurality of radial and spiral camming slots, a second plurality of pins secured to said fourth disc, a plurality of linkage members secured to said respective first plurality of pins adjacent said fourth disc and slidably mounted on said second plurality of pins, and a plurality of fan blades secured to the outer ends of said respective plurality of linkage members, the resultant camming action of said cooperating radial and spiral camming slots causing said plurality of fan blades to move radially inwardly to decrease the overall diameter thereof in response to the radial outward movement of said centrifugal weight members under the action of centrifugal force. 